Current sensor for improved functional safety

ABSTRACT

A current sensor arrangement includes a first conductor configured to conduct a first portion of a primary current in a current flow direction; a second conductor configured to conduct a second portion of the primary current in the current flow direction; and a magnetic sensor. The first and second conductor are coupled in parallel. The first current produces a first magnetic field as it flows through the first conductor and the second current produces a second magnetic field as it flows through the second conductor. The first conductor and the second conductor are separated from each other in a first direction that is orthogonal to the current flow direction, thereby defining a gap. The magnetic sensor is arranged in the gap such that the first conductor is arranged over a first portion of the magnetic sensor and the second conductor is arranged under a second portion of the magnetic sensor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/800,042 filed Feb. 25, 2020, which is incorporated by reference as iffully set forth.

FIELD

The present disclosure relates generally to a current sensor device andto methods for current sensing, and, more particularly, to a diversecurrent sensor device and to methods for diverse current sensing.

BACKGROUND

There are many application for a current sensor. As one example, thecurrent sensor is an integral part of a battery system of an electricvehicle. It also plays an important role in the board net architectureof conventional vehicles. New applications, like automated driving,increase the requirements on current sensors concerning functionalsafety, which includes redundant or diverse current sensing and theability to detect faulty current sensors.

In electric vehicles there are two main types of current sensors used,shunt based (i.e., resistive based) and Hall-effect based(magnetic-based). In order to improve the functional safety rating of acurrent sensor, two diverse measurement principles like resistive-basedand magnetic-based sensing could be combined. However, combining twodiverse sensors may lead to bulky and expensive solutions.

Therefore, a current sensing device that uses a diverse currentmeasurement principle without the above-noted disadvantages may bedesirable.

SUMMARY

According to one or more embodiments, a current sensor arrangementincludes a conductor configured to conduct a primary current, theconductor including a first end, a second end oppositely arranged withrespect to the first end, and a slit that extends partially between thefirst end and the second end in a current flow direction. The slitdivides the conductor into a first conductor portion and a secondconductor portion both conjoined at the first end and the second end ofthe conductor. The primary current flows in the current flow directionfrom the first end to the second end. The primary current is dividedinto a first current that produces a first magnetic field as it flowsthrough the first conductor portion in the current flow direction and asecond current that produces a second magnetic field as it flows throughthe second conductor portion in the current flow direction. The firstconductor portion and the second conductor portion are separated fromeach other in a first direction that is orthogonal to the current flowdirection, thereby defining a gap. The current sensor arrangementfurther includes a magnetic sensor arranged in the gap such that thefirst conductor portion is arranged over a first portion of the magneticsensor and the second conductor portion is arranged under a secondportion of the magnetic sensor.

According to one or more embodiments, a method of manufacturing acurrent sensor arrangement includes providing a conductor that isconfigured to conduct a primary current, the conductor including a firstend and a second end oppositely arranged with respect to the first endwith respect to a current flow direction of the primary current; forminga current impeding structure across the conductor in a bisecting mannerin a first direction that is orthogonal to the current flow direction;forming a slit in the conductor that extends partially between the firstend and the second end in the current flow direction, where the slitextends through the current impeding structure in the current flowdirection and through the conductor in a second direction that isorthogonal to the current flow direction, where the slit divides theconductor into a first conductor portion and a second conductor portionboth conjoined at the first end and the second end of the conductor;deforming the first conductor portion and the second conductor portionin opposite directions with respect to second direction, therebydefining a gap; and inserting magnetic sensor through the gap such thatthe first conductor portion is arranged over a first portion of themagnetic sensor and the second conductor portion is arranged under asecond portion of the magnetic sensor.

According to one or more embodiments, a current sensor arrangementincludes a first conductor configured to conduct a first portion of aprimary current along a first current path in a current flow direction;a second conductor configured to conduct a second portion of the primarycurrent along a second current path in the current flow direction, wherethe first conductor and the second conductor are coupled in parallel.The first current produces a first magnetic field as it flows throughthe first conductor and the second current produces a second magneticfield as it flows through the second conductor. The first conductor andthe second conductor are separated from each other in a first directionthat is orthogonal to the current flow direction, thereby defining agap. The current sensor arrangement further includes a magnetic sensorarranged in the gap such that the first conductor is arranged over afirst portion of the magnetic sensor and the second conductor isarranged under a second portion of the magnetic sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are described herein making reference to the appendeddrawings.

FIG. 1A is a perspective view of a diverse current sensor according toone or more embodiments;

FIG. 1B is a plan view of the diverse current sensor shown in FIG. 1A;

FIG. 1C is a cross-sectional view of the diverse current sensor takenalong cut line A-A shown in FIG. 1B; and

FIG. 2 is a perspective view of a conductor used in the diverse currentsensor according to one or more embodiments.

DETAILED DESCRIPTION

In the following, details are set forth to provide a more thoroughexplanation of the exemplary embodiments. However, it will be apparentto those skilled in the art that embodiments may be practiced withoutthese specific details. In other instances, well-known structures anddevices are shown in block diagram form or in a schematic view ratherthan in detail in order to avoid obscuring the embodiments. In addition,features of the different embodiments described hereinafter may becombined with each other, unless specifically noted otherwise.

Further, equivalent or like elements or elements with equivalent or likefunctionality are denoted in the following description with equivalentor like reference numerals. As the same or functionally equivalentelements are given the same reference numbers in the figures, a repeateddescription for elements provided with the same reference numbers may beomitted. Hence, descriptions provided for elements having the same orlike reference numbers are mutually exchangeable.

Directional terminology, such as “top”, “bottom”, “above”, “below”,“front”, “back”, “behind”, “leading”, “trailing”, “over”, “under”, etc.,may be used with reference to the orientation of the figures and/orelements being described. Because the embodiments can be positioned in anumber of different orientations, the directional terminology is usedfor purposes of illustration and is in no way limiting. In someinstances, directional terminology may be exchanged with equivalentdirectional terminology based on the orientation of an embodiment solong as the general directional relationships between elements, and thegeneral purpose thereof, is maintained.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.).

In embodiments described herein or shown in the drawings, any directelectrical connection or coupling, i.e., any connection or couplingwithout additional intervening elements, may also be implemented by anindirect connection or coupling, i.e., a connection or coupling with oneor more additional intervening elements, or vice versa, as long as thegeneral purpose of the connection or coupling, for example, to transmita certain kind of signal or to transmit a certain kind of information,is essentially maintained. Features from different embodiments may becombined to form further embodiments. For example, variations ormodifications described with respect to one of the embodiments may alsobe applicable to other embodiments unless noted to the contrary.

The term “substantially” may be used herein to account for smallmanufacturing tolerances (e.g., within 5%) that are deemed acceptable inthe industry without departing from the aspects of the embodimentsdescribed herein.

Embodiments relate to sensors and sensor systems, and to current sensorsand current sensor systems. In general, a sensor may refer to acomponent which converts a physical quantity to be measured to anelectric signal, for example, a current signal or a voltage signal. Thephysical quantity may for example comprise a magnetic field, an electricfield, a pressure, a force, a current or a voltage, but is not limitedthereto. It will be appreciated that there are various sensor techniquefor measuring current, as will be described in the followingembodiments.

A magnetic field sensor, for example, includes one or more magneticfield sensor elements that measure one or more characteristics of amagnetic field (e.g., an amount of magnetic field flux density, a fieldstrength, a field angle, a field direction, a field orientation, etc.).The magnetic field may be produced by a magnet, a current-carryingconductor (e.g., a wire), the Earth, or other magnetic field source.Each magnetic field sensor element is configured to generate a sensorsignal (e.g., a voltage signal) in response to one or more magneticfields impinging on the sensor element. Thus, a sensor signal isindicative of the magnitude and/or the orientation of the magnetic fieldimpinging on the sensor element.

Magnetic sensors include magnetoresistive sensors and Hall-effectsensors (Hall sensors), for example. Magnetoresistance is a property ofa material to change the value of its electrical resistance when anexternal magnetic field is applied to it. Some examples ofmagnetoresistive effects are Giant Magneto-Resistance (GMR), which is aquantum mechanical magnetoresistance effect observed in thin-filmstructures composed of alternating ferromagnetic and non-magneticconductive layers, Tunnel Magneto-Resistance (TMR), which is amagnetoresistive effect that occurs in a magnetic tunnel junction (MTJ),which is a component consisting of two ferromagnets separated by a thininsulator, or Anisotropic Magneto-Resistance (AMR), which is a propertyof a material in which a dependence of electrical resistance on theangle between the direction of electric current and direction ofmagnetization is observed. For example, in the case of AMR sensors, aresistance for an AMR sensor element changes according to a square of asine of an angle of the magnetic field component projected on a sensingaxis of the ARM sensor element.

The plurality of different magnetoresistive effects is commonlyabbreviated as xMR, wherein the “x” acts as a placeholder for thevarious magnetoresistive effects. xMR sensors can detect the orientationof an applied magnetic field by measuring sine and cosine anglecomponents with monolithically integrated magnetoresistive sensorelements.

A magnetic field component may be, for example, an x-magnetic fieldcomponent (Bx), a y-magnetic field component (By), or a z-magnetic fieldcomponent (Bz), where the Bx and By field components are in-plane to thechip, and Bz is out-of-plane to the chip in the examples provided.

Magnetoresistive sensor elements of such xMR sensors typically include aplurality of layers, of which at least one layer is a reference layerwith a reference magnetization (i.e., a reference direction). Thereference magnetization provides a sensing direction corresponding to asensing axis of the xMR sensor. Accordingly, if a magnetic fieldcomponent points exactly in the same direction as the referencedirection, a resistance of the xMR sensor element is at a maximum, and,if a magnetic field component points exactly in the opposite directionas the reference direction, the resistance of the xMR sensor element isat a minimum. In some applications, an xMR sensor includes a pluralityof magnetoresistive sensor elements, which have the same or differentreference magnetizations.

A Hall effect sensor is a transducer that varies its output voltage(Hall voltage) in response to a magnetic field. It is based on the Halleffect which makes use of the Lorentz force. The Lorentz force deflectsmoving charges in the presence of a magnetic field which isperpendicular to the current flow through the sensor or Hall plate.Thereby, a Hall plate can be a thin piece of semiconductor or metal. Thedeflection causes a charge separation which causes a Hall electricalfield. This electrical field acts on the charge in the oppositedirection with regard to the Lorentz Force. Both forces balance eachother and create a potential difference perpendicular to the directionof current flow. The potential difference can be measured as a Hallvoltage and varies in a linear relationship with the magnetic field forsmall values. Hall effect sensors can be used for proximity switching,positioning, speed detection, and current sensing applications.

A vertical Hall sensor is a magnetic field sensor constructed with theHall element perpendicular to the plane of the chip (e.g., extendingfrom a main surface of the chip into the chip body). It senses magneticfields perpendicular to its defined sensitive edge (top, right, or left,relative to the main surface of the chip). This generally means that avertical Hall sensor is sensitive to a magnetic field component thatextends parallel to their surface and parallel, or in-plane, to the mainsurface of the chip in which the vertical Hall sensor is integrated. Inparticular, a vertical Hall sensor may extend from the main surface intothe chip. The plane of sensitivity may be referred to herein as a“sensitivity-axis” or “sensing axis” and each sensing axis has areference direction. For vertical Hall sensor elements, voltage valuesoutput by the sensor elements change according to the magnetic fieldstrength in the direction of its sensing axis.

On the other hand, a lateral (planar) Hall sensor is constructed withthe Hall element in the same plane as the main surface of the chip. Itsenses magnetic fields perpendicular to its planar surface. This meansthey are sensitive to magnetic fields vertical, or out-of-plane, to themain surface of the chip. The plane of sensitivity may be referred toherein as a “sensitivity-axis” or “sensing axis” and each sensing axishas a reference direction. Similar to vertical Hall sensor elements,voltage values output by lateral Hall sensor elements change accordingto the magnetic field strength in the direction of its sensing axis.

Embodiments may be directed specifically to magnetic sensors that aresensitive to magnetic fields that are parallel to the chip plane formeasuring magnetic fields produced by a current. Thus, xMR sensors andvertical Hall sensors may be used because both are sensitive to magneticfields in the chip plane.

A magnetic field sensor, as provided herein, may be used as a currentsensor. For example, the magnetic field sensor can be used as a currentsensor if it is coupled to a magnetic field generated by some current tobe measured which flows through some primary conductor. For example,contactless current measurement can be accomplished by using themagnetic field sensor to sense the magnetic field caused by a currentpassing through a conductor. The magnetic field caused by the currentdepends on the magnitude of the current. For example, for a longstraight wire carrying a current i, the magnitude of the resultingmagnetic field H at a distance d from the wire is directly proportionalto the current i. In accordance to the Biot-Savart law, the magnitude ofthe magnetic field H equals H=i/(2πd) if the wire is very long(theoretically infinitely long) as compared to the distance d.

According to one or more embodiments, a plurality of magnetic fieldsensors and a sensor circuitry may be both accommodated (i.e.,integrated) in the same chip. The sensor circuit may be referred to as asignal processing circuit and/or a signal conditioning circuit thatreceives one or more signals (i.e., sensor signals) from one or moremagnetic field sensor elements in the form of raw measurement data andderives, from the sensor signal, a measurement signal that representsthe magnetic field.

In some cases, a measurement signal may be differential measurementsignal that is derived from sensor signals generated by two sensorelements having a same sensing axis (e.g., two sensor elements sensitiveto the same magnetic field component) using differential calculus. Adifferential measurement signal provides robustness to homogenousexternal stray magnetic fields.

Signal conditioning, as used herein, refers to manipulating an analogsignal in such a way that the signal meets the requirements of a nextstage for further processing. Signal conditioning may include convertingfrom analog to digital (e.g., via an analog-to-digital converter),amplification, filtering, converting, biasing, range matching, isolationand any other processes required to make a sensor output suitable forprocessing after conditioning.

Thus, the sensor circuit may include an analog-to-digital converter(ADC) that converts the analog signal from the one or more sensorelements to a digital signal. The sensor circuit may also include adigital signal processor (DSP) that performs some processing on thedigital signal, to be discussed below. Therefore, a chip, which may alsobe referred to as an integrated circuit (IC), may include a circuit thatconditions and amplifies the small signal of one or more magnetic fieldsensor elements via signal processing and/or conditioning.

A sensor device, as used herein, may refer to a device which includes asensor and sensor circuit as described above. A sensor device may beintegrated on a single semiconductor die (e.g., silicon die or chip).Thus, the sensor and the sensor circuit are disposed on the samesemiconductor die.

Embodiments combine a current sense resistor, such as a shunt resistor,with a magnetic current sensor by inserting the magnetic current sensorinto the current sense resistor in a dedicated way. In particular, ashape of the current sense resistor is modified to enable differentialsensing of the magnetic field caused by the current flow through thecurrent sense resistor. This decreases susceptibility to externalmagnetic fields. Since the magnetic current sensor is integrated intothe current sense resistor there is no additional space needed andtherefore the overall size of the diverse sensor system is reduced.Furthermore, by combining two diverse measurement principles likeresistive and magnetic based sensing, the functional safety rating isimproved.

FIG. 1A is a perspective view of a diverse current sensor 100 accordingto one or more embodiments. FIG. 1B is a plan view of the diversecurrent sensor 100 shown in FIG. 1A. FIG. 1C is a cross-sectional viewof the diverse current sensor 100 taken along cut line A-A shown in FIG.1B.

The diverse current sensor 100 includes a conductor 10 that includes afirst conjoined end 11 and a second conjoined end 12. The conductor 10may be, for example, a current rail or busbar made of copper or otherelectrically conductive material. The conductor 10 is configured toconduct a primary current Ip from the first conjoined end 11 to thesecond conjoined end 12, or vice versa. For example, the first conjoinedend 11 may be an input lead configured to be connected to a powersupply, such as a battery. The second conjoined end 12 may be an outputlead that is configured to be connected to a load, such as a motorphase.

The conductor 10 further includes a slit 14 interposed between the twoconjoined ends 11 and 12. In particular, the slit 14 is a cut thatextends entirely through a thickness of the conductor and also extendsalong the current flow direction in a lengthwise direction of theconductor 10. The conductor 10 may further include a first crack stop 15and a second crack stop 16 located at opposing ends of the slit 14. Thefirst crack stop 15 and the second crack stop 16 prevent the slit 14from enlarging beyond the boundaries defined by the first and secondcrack stops 15, 16.

The slit 14 separates the conductor 10 into a first conductor portion 18(i.e., a first current path) and a second conductor portion 19 (i.e., asecond current path) that are conjoined at both of the two conjoinedends 11 and 12. Thus, the first conductor portion 18 and the secondconductor portion 19 represent two parallel conducting paths having ashared current source (i.e., a same current input) and a shared currentsink (i.e., a same current output). Both the first conductor portion 18and a second conductor portion 19 extend along the current flowdirection between the two conjoined ends 11 and 12. Both the firstconductor portion 18 and a second conductor portion 19 are configured toconduct or carry equal or substantially equal portions of the primarycurrent Ip. Thus, the first conductor portion 18 conducts a firstcurrent I1 derived from the primary current Ip and the second conductorportion 18 conducts a second current I2 derived from the same primarycurrent Ip.

The conductor 10 further includes two current impeding structures, eachof which induce a voltage difference across its body as a current flowstherethrough. For example, a first shunt resistor 21 is arranged in thefirst conductor portion 18 in a bisecting manner to the current flow(i.e., orthogonal to the first current path) and a second shunt resistor22 is arranged in the second conductor portion 19 in a bisecting mannerto the current flow (i.e., orthogonal to the second current path). Thefirst and the second shunt resistors 21 and 22 may be made nickel,chromium, or alloys thereof, but is not limited thereto. For example,the first and the second shunt resistors 21 and 22 may be made manganinthat has a composition of copper, manganese, and nickel.

The conductor 10 may be bent or deformed such that the first conductorportion 18 and the second conductor portion 19 separate from each otherat the slit 14 in two opposing directions. The two opposing directionsmay be regarded as parallel to the thickness direction of the conductor10, orthogonal to the length direction of the conductor 10, ororthogonal to the direction of the current flow between the first end 11and the second end 12. For example, the first conductor portion 18 maybe bent upward (or downward) and the second conductor portion 19 may bebent downward (or upward) such that a gap 23 is formed between the firstconductor portion 18 and the second conductor portion 19.

The diverse current sensor 100 further includes a differential magneticsensor 30 that has a first main surface 31 (e.g., a first chip surface)and a second main surface 32 (e.g., a second chip surface) arrangedopposite to the first main surface 31 in a direction parallel to thethickness direction of the conductor 10. The differential magneticsensor 30 is inserted into the gap 23 formed between the first conductorportion 18 and the second conductor portion 19. In this way, the firstconductor portion 18 overlaps with a portion of the first main surface31 and the second conductor portion 19 overlaps with a portion of thesecond main surface 32. Thus, the differential magnetic sensor 30resides below the first current path I1 and above the second currentpath I2, which is made more apparent in FIG. 1C.

The differential magnetic sensor 30 includes a first sensing element 33and a second sensing element 34 arranged in a differentialconfiguration. In particular, the first sensing element 33 and thesecond sensing element 34 are sensitive to the same magnetic fieldcomponent of the magnetic fields generated by the first current I1flowing through the first conductor portion 18 and the second current I2flowing through the second conductor portion 19, respectively. In aconfiguration in which the two current impeding structures are provided,the first sensing element 33 and the second sensing element 34 aresensitive to the same magnetic field component of the magnetic fieldsgenerated by the first current I1 flowing through the first conductorportion 18 and the first shunt resistor 21 and the second current I2flowing through the second conductor portion 19 and the second shuntresistor 22, respectively. For example, their sensing axis or referencedirection may be aligned parallel or antiparallel with each other tomeasure the same magnetic field component that is in the chip plane(i.e., same plane as the main surfaces 31 and 32). Both sensing elements33 and 34 generate sensor signals in response to measuring the magneticfield component of a magnetic field impinging thereon. The sensorsignals are representative of a magnetic field strength of the magneticfield component.

Additionally, while the first sensing element 33 may be a single sensorelement it may also be a group of sensor elements that are arranged in aWheatstone-bridge configuration, with each sensor element beingsensitive to the same magnetic field component. The Wheatstone-bridgeconfiguration may output a single sensor signal as a first sensorsignal.

Similarly, while the second sensing element 34 may be a single sensorelement it may also be a group of individual sensor elements that arearranged in a Wheatstone-bridge configuration, with each sensor elementbeing sensitive to the same magnetic field component. TheWheatstone-bridge configuration may output a single sensor signal as asecond sensor signal.

The differential magnetic sensor 30 further includes lead wires 35 thatinput or output various signals to the differential magnetic sensor 30.For example, the lead wires 35 may output the sensor signals generatedby the sensing elements 33 and 34. In addition, the lead wires 35 mayprovide a first supply potential (e.g., a source voltage) and a secondsupply potential (e.g., ground potential) to the sensing elements 33 and34.

The diverse current sensor 100 may further include measurement circuitrythat includes a differential operational amplifier 41 and a processingcircuit 42.

The differential operational amplifier 41 includes two inputs 41 a and41 b that are connected across one of the shunt resistors 21 or 22. Inthis example, the two inputs 41 a and 41 b that are connected to twolocations of the first conductor portion 18 across shunt resistor 21 inorder to measure a difference in potential across the shunt resistor 21.The differential operational amplifier 41 generates an output signal(e.g., a voltage) representative of the difference in potential acrossthe shunt resistor 21 and outputs the output signal from its output 41c. It will be appreciated that another type of circuit component orsuitable circuit capable of tapping the two potentials across the shuntresistor 21 and generating an output signal representative of thedifference in potential (i.e., representative of the voltage drop) mayalso be used.

The processing circuit 42 may be analog circuitry, a digital circuitry,such as a microprocessor or digital signal processor, or a combinationof analog circuitry and digital circuitry. The processing circuit 42receives the analog measurement signals from the differential magneticsensor 30 and the differential operational amplifier 41 and performsprocessing and analysis thereon. These analog measurement signalsinclude the sensor signals generated by the sensing elements 33 and 34and the output signal generated by the differential operationalamplifier 41. The processing circuit 42 is configured to calculate thefirst current I1 based on the output signal and by applying Ohm's Law,with the resistance across the first shunt resistor 21 being known andstored in memory. The processing circuit 42 is further configured tocalculate the first current I1 based on the sensor signals.

In particular, current I1 flowing through the first shunt resistor 21creates a first magnetic field 51 that is parallel to the conductorsurface of the first conductor portion 18 and perpendicular to thecurrent flow direction of the current I1. Similarly, current I2 flowingthrough the second shunt resistor 22 creates a second magnetic field 52that is parallel to the conductor surface of the second conductorportion 19 and perpendicular to the current flow direction of thecurrent I2. The differential magnetic sensor 30 uses a measurementprinciple which is sensitive to magnetic fields in the chip plane, suchas those based on vertical Hall-effect sensors or the AMR-effect, theGMR-effect, or the TMR-effect. Thus, these types of magnetic sensorsused for the sensing elements 33 and 34 are suited to pick up the abovedescribed fields generated by the current lines 18 and 19.

The first sensing element 33 is arranged within the first magnetic field51 and is positioned such that a lateral or in-plane component of thefirst magnetic field 51 intersects with the sensing axis of the sensingelement 33. As a result, sensing element 33 is arranged to measure thelateral or in-plane component of the first magnetic field 51 andgenerate a first sensor signal based thereon. In this example, thesensing element 33 is arranged under the first conductor portion 18. Inother words, the sensing element 33 is arranged such that the sensingelement 33 and the first conductor portion 18 overlap in the thicknessdirection of the conductor 10 (i.e., in the thickness direction of thefirst conductor portion 18), which is orthogonal to the current flow ofthe first current I1.

Similarly, the second sensing element 34 is arranged within the secondmagnetic field 52 and is positioned such that a lateral or in-planecomponent of the second magnetic field 52 intersects with the sensingaxis of the sensing element 34. As a result, sensing element 34 isarranged to measure the lateral or in-plane component of the secondmagnetic field 52 and generate a second sensor signal based thereon. Inthis example, the sensing element 34 is arranged above the secondconductor portion 19. In other words, the sensing element 34 is arrangedsuch that the sensing element 34 and the second conductor portion 19overlap in the thickness direction of the conductor 10 (i.e., in thethickness direction of the second conductor portion 19), which isorthogonal to the current flow of the second current I2.

As can be seen in FIG. 1C, by placing the sensor elements 33 and 34 in adifferential configuration below the first current path I1 and above thesecond current path 12, respectively, the sensor elements 33 and 34receive magnetic fields 51 and 52 that are substantially equal butopposite in direction. The processing circuit 42 may be configured togenerate a differential sensor signal based on the first sensor signaland the second sensor signal wherein the differential sensor signal isrobust against positioning tolerances and robust against disturbancefields. For example, the processing circuit 42 may calculate an averageof the magnitudes (i.e., absolute values) of the first and second sensorsignals to derive the differential sensor signal. Alternatively, theprocessing circuit 42 may subtract one of the sensor signals from theother sensor signal to derive the differential sensor signal. In eithercase, the calculated value of the differential sensor signal should besubstantially equal (i.e., within a predetermined tolerance range) tothe value of the output signal generated by the differential operationalamplifier 41. If not, an error or fault may exist and this error orfault can be detected by the processing circuit 42 using a comparisonoperation.

For fault detection, the processing circuit 42 may calculate adifference between the output signal generated by the differentialoperational amplifier 41 and the differential sensor signal, compare thecalculated difference to a predetermined threshold or threshold range,and detect a fault on a condition that the calculated difference exceedsthe predetermined threshold or threshold range. If this condition issatisfied, the processing circuit 42 may be configured to generate andoutput a fault signal indicating that an error or fault occurred in thesystem. Otherwise, the processing circuit 42 determines that the systemis operating normally and a fault signal is not generated.

By using two parallel conducting paths 18 and 19 and placing the sensorelements 33 and 34 in a differential configuration below the firstcurrent path I1 and above the second current path I2, respectively, theentire magnetic field sensor setup is robust against positioningtolerances, robust against disturbance fields, and efficient withrespect to space consumption. By comparing both sensor readings(magnetics and shunt based) the results can be validated and amalfunction of the sensor can be detected, therefore improving thefunctional safety rating of the combined sensor versus a single sensor.

Further embodiments may include a temperature sensor used fortemperature compensation of the sensor signals, an amplification circuitused to amplify the sensor signals, a circuit for fast current thresholddetection (i.e., overcurrent detection), copper busbars used instead ofshunts 21 and 22 (with increased temperature dependency), and/or copperbusbars used instead of shunts 21 and 22 plus temperature sensors usedfor temperature compensation of the sensor signals.

For overcurrent detection, the processing circuit 42 may compare valuesof both the output signal and the differential sensor signal to anovercurrent threshold, and generate and output an overcurrent faultsignal on a condition that at least one of the signal values exceed theovercurrent threshold.

FIG. 2 is a perspective view of the conductor 10 used in the diversecurrent sensor 100 according to one or more embodiments. In particular,the conductor 10 is shown prior to separating the first conductorportion 18 and the second conductor portion 19. Here, a current impedingstructure 20 is formed between the two conjoined ends 11 and 12 of theconductor 10. The current impeding structure 20 bisects the conductor 10orthogonal to the direction of current flow so that a current passesthrough the current impeding structure 20. After the current impedingstructure 20 is formed, the conductor 10 may be cut to form the slit 14.Crack stops 15 and 16 may also be formed at opposing ends of the slit 14to prevent the slit 14 from being enlarged beyond the boundaries of thecrack stops 15 and 16 during bending to form the first conductor portion18 and the second conductor portion 19. The two parallel portions of theconductor 10 may then be bent in opposite directions to form the gap 23shown in FIG. 1A. As a result, the first conductor portion 18 and thesecond conductor portion 19 are formed with their respective shuntresistors 21 and 22 being portions of the current impeding structure 20that have been also split apart by the bending or deforming. Thedifferential magnetic sensor 30 may then be inserted into the gap 23 andthe measurement circuitry coupled to receive the sensor signals and tomeasure the voltage drop across one of the shunt resistors 21 or 22giving a measure of the current flow.

The method of inserting the magnetic-based sensor into the conductorenables space savings and reduction of power losses while stillmaintaining differential sensing. The differential arrangement of thesensing elements enables a robust differential measurement of themagnetic field using straight conductors with the current flowing in thesame direction. Furthermore, the diverse combination of shunt-based andmagnetic-based sensing improves the functional safety of the overalldevice.

It will be further appreciated that two conductor strips, connected inparallel, may be used as the first conductor portion 18 and the secondconductor portion 19.

Alternatively, the two conjoined ends 11 and 12 may be separateconductor pieces that may be coupled or bonded together via the shunts21 and 22. In this case, each conjoined end 11 and 12 includes itsrespective portion (e.g., half) of the first conductor portion 18 andthe second conductor portion 19. Shunt 21 is used to couple the twofirst conductor portions 18 together and the shunt 22 is used to couplethe two second conductor portions 19 together. The two first conductorportions 18 and the two second conductor portions 19 can be similarlyformed as described above by first forming a slit 14 partially along thecurrent flow direction in each conjoined end 11 and 12 (i.e., from oneside of a conductor portion towards an opposite side of the conductorportion), and then deforming the two conductor portions 18 and 19 ofeach conjoined end 11 and 12 in opposite directions. Once the twoconductor portions 18 and 19 of each conjoined end 11 and 12 aredeformed, the two conjoined ends 11 and 12 can be coupled together byshunts 21 and 22 to form the structure illustrated in FIGS. 1A-1C. Here,mechanical fasteners may also be used to couple the parts together.

While various embodiments have been described, it will be apparent tothose of ordinary skill in the art that many more embodiments andimplementations are possible within the scope of the disclosure.Accordingly, the invention is not to be restricted except in light ofthe attached claims and their equivalents. With regard to the variousfunctions performed by the components or structures described above(assemblies, devices, circuits, systems, etc.), the terms (including areference to a “means”) used to describe such components are intended tocorrespond, unless otherwise indicated, to any component or structurethat performs the specified function of the described component (i.e.,that is functionally equivalent), even if not structurally equivalent tothe disclosed structure that performs the function in the exemplaryimplementations of the invention illustrated herein.

Furthermore, the following claims are hereby incorporated into thedetailed description, where each claim may stand on its own as aseparate example embodiment. While each claim may stand on its own as aseparate example embodiment, it is to be noted that—although a dependentclaim may refer in the claims to a specific combination with one or moreother claims—other example embodiments may also include a combination ofthe dependent claim with the subject matter of each other dependent orindependent claim. Such combinations are proposed herein unless it isstated that a specific combination is not intended. Furthermore, it isintended to include also features of a claim to any other independentclaim even if this claim is not directly made dependent to theindependent claim.

It is further to be noted that methods disclosed in the specification orin the claims may be implemented by a device having means for performingeach of the respective acts of these methods.

Further, it is to be understood that the disclosure of multiple acts orfunctions disclosed in the specification or claims may not be construedas to be within the specific order. Therefore, the disclosure ofmultiple acts or functions will not limit these to a particular orderunless such acts or functions are not interchangeable for technicalreasons. Furthermore, in some embodiments a single act may include ormay be broken into multiple sub acts. Such sub acts may be included andpart of the disclosure of this single act unless explicitly excluded.

The techniques described in this disclosure may be implemented, at leastin part, in hardware, software, firmware, or any combination thereof.For example, various aspects of the described techniques may beimplemented within one or more processors, including one or moremicroprocessors, digital signal processors (DSPs), application specificintegrated circuits (ASICs), or any other equivalent integrated ordiscrete logic circuitry, as well as any combinations of suchcomponents. The term “processor” or “processing circuitry” may generallyrefer to any of the foregoing logic circuitry, alone or in combinationwith other logic circuitry, or any other equivalent circuitry. A controlunit including hardware may also perform one or more of the techniquesof this disclosure. Such hardware, software, and firmware may beimplemented within the same device or within separate devices to supportthe various techniques described in this disclosure.

Although various exemplary embodiments have been disclosed, it will beapparent to those skilled in the art that various changes andmodifications can be made which will achieve some of the advantages ofthe concepts disclosed herein without departing from the spirit andscope of the invention. It will be obvious to those reasonably skilledin the art that other components performing the same functions may besuitably substituted. It is to be understood that other embodiments maybe utilized and structural or logical changes may be made withoutdeparting from the scope of the present invention. It should bementioned that features explained with reference to a specific figuremay be combined with features of other figures, even in those notexplicitly mentioned. Such modifications to the general inventiveconcept are intended to be covered by the appended claims and theirlegal equivalents.

What is claimed is:
 1. A method of manufacturing a current sensorarrangement, the method comprising: providing a first conductor piecethat is configured to conduct a primary current, the first conductorpiece comprising a first end and a second end oppositely arrangedrelative to the first end with respect to a current path of the primarycurrent; forming a first slit in the first conductor piece that extendspartially from the first end towards the second end along the currentpath, wherein the first slit divides the first conductor piece into afirst conductor portion and a second conductor portion both conjoined atthe second end of the first conductor piece; providing a secondconductor piece that is configured to conduct the primary current, thesecond conductor piece comprising a third end and a fourth endoppositely arranged relative to the second end with respect to thecurrent path of the primary current; forming a second slit in the secondconductor piece that extends partially from the third end towards thefourth end along the current path, wherein the second slit divides thesecond conductor piece into a third conductor portion and a fourthconductor portion both conjoined at the fourth end of the secondconductor piece; deforming the first conductor portion and the secondconductor portion in opposite directions; deforming the third conductorportion and the fourth conductor portion in opposite directions;conjoining the first conductor portion and the third conductor portionvia a first current impeding structure to form a first conjoinedconductor structure; conjoining the second conductor portion and thefourth conductor portion via a second current impeding structure to forma second conjoined conductor structure; and inserting a magnetic sensorthrough a gap formed between the first conjoined conductor structure andthe second conjoined conductor structure such that the first conjoinedconductor structure is arranged over a first portion of the magneticsensor and the second conjoined conductor structure is arranged under asecond portion of the magnetic sensor.
 2. The method of manufacturing ofclaim 1, wherein: the first current impeding structure is formed inbisecting manner to a current path in the first conjoined conductorstructure, and the second current impeding structure is formed inbisecting manner to a current path in the second conjoined conductorstructure.
 3. The method of manufacturing of claim 1, furthercomprising: electrically connecting a measurement circuit across thefirst current impeding structure or the second current impedingstructure, wherein the measurement circuit is configured to measure avoltage drop across the first current impeding structure or the secondcurrent impeding structure.
 4. The method of manufacturing of claim 1,further comprising: electrically connecting a processing circuit to themagnetic sensor, the processing circuit configured to receive sensorsignals generated by the magnetic sensor in response to measuring afirst magnetic field produced by a first current flowing through thefirst current impeding structure and in response to measuring a secondmagnetic field produced by a second current flowing through the secondcurrent impeding structure.
 5. The method of manufacturing of claim 4,wherein: the magnetic sensor is configured to generate a first sensorsignal based on the first magnetic field impinging the first portion ofthe magnetic sensor and generate a second sensor signal based on thesecond magnetic field impinging the second portion of the magneticsensor.
 6. The method of manufacturing of claim 4, wherein: the magneticsensor includes at least one first sensing element arranged in the firstportion of the magnetic sensor and within the first magnetic field, theat least one first sensing element configured to generate a first sensorsignal based on the first magnetic field impinging thereon, and themagnetic sensor includes at least one second sensing element arranged inthe second portion of the magnetic sensor and within the second magneticfield, the at least one second sensing element configured to generate asecond sensor signal based on the second magnetic field impingingthereon.
 7. The method of manufacturing of claim 6, wherein: each of theat least one first sensing element comprises a first sensing axis andthe at least one first sensing element is configured to generate thefirst sensor signal in response to a magnetic field component of thefirst magnetic field being projected onto each first sensing axis, eachof the at least one second sensing element comprises a second sensingaxis and the at least one second sensing element is configured togenerate the second sensor signal in response to a magnetic fieldcomponent of the second magnetic field being projected onto each secondsensing axis, and each first sensing axis is parallel or antiparallel toeach second sensing axis.
 8. The method of manufacturing of claim 6,wherein: the magnetic sensor comprises a first main surface and a secondmain surface arranged opposite to the first main surface, and the atleast one first sensing element and the at least one second sensingelement are sensitive to magnetic field components of the first magneticfield and the second magnetic field that extend parallel to the firstmain surface and the second main surface and that extend orthogonal tothe current path.
 9. The method of manufacturing of claim 6, wherein:the at least one first sensing element is arranged in the first portionof the magnetic sensor such that the first magnetic field is projectedonto the at least one first sensing element in parallel to a conductorsurface of the first conjoined conductor structure and orthogonal to thecurrent path, and the at least one second sensing element is arranged inthe second portion of the magnetic sensor such that the second magneticfield is projected onto the at least one second sensing element inparallel to a conductor surface of the second conjoined conductorstructure and orthogonal to the current path.
 10. The method ofmanufacturing of claim 4, wherein the first current impeding structureis a first shunt resistor having a first resistance and the secondcurrent impeding structure is a second shunt resistor having a secondresistance that is substantially equal to the first resistance such thatthe first current and the second current are substantially equal. 11.The method of manufacturing of claim 1, wherein the first currentimpeding structure is a first shunt resistor having a first resistanceand the second current impeding structure is a second shunt resistorhaving a second resistance that is substantially equal to the firstresistance.
 12. The method of manufacturing of claim 1, wherein: thefirst current impeding structure is configured to produce a firstmagnetic field that is projected onto the magnetic sensor, and thesecond current impeding structure is configured to produce a secondmagnetic field that is projected onto the magnetic sensor.
 13. Themethod of manufacturing of claim 1, wherein the magnetic sensor is aunitary semiconductor chip.
 14. The method of manufacturing of claim 1,wherein the first conjoined conductor structure and the second conjoinedconductor structure are coupled in parallel.
 15. The method ofmanufacturing of claim 3, wherein the measurement circuit includes afirst electrical contact to the first conductor portion and a secondelectrical contact to the third conductor portion for measuring thevoltage drop across the first current impeding structure or includes afirst electrical contact to the second conductor portion and a secondelectrical contact to the fourth conductor portion for measuring thevoltage drop across the second current impeding structure.
 16. Themethod of manufacturing of claim 15, wherein the measurement circuit isa non-magnetic field measurement circuit.
 17. The method ofmanufacturing of claim 1, wherein the first current impeding structurebisects an entire width of the first conjoined conductor structure andthe second current impeding structure bisects an entire width of thesecond conjoined conductor structure.